﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class StringUtil
    {
        public void judge()
        {
            Console.WriteLine("请输入一串字符串");
            string str = Console.ReadLine();

            if (str is null || str == "" || string.IsNullOrWhiteSpace(str))
            {
                Console.WriteLine("请输入");
            }

        }

       

    }

}
